text: V. G. Khlopin began his independent scientific activity as a student in 1911 - in his father's laboratory at the Clinical Institute he carried out work, the results of which were published in the article "On the formation of oxidants in the air under the action of ultraviolet rays".
  In these studies V. G. Khlopin first proved the formation in atmospheric air under the action of ultraviolet rays not only hydrogen peroxide and ozone, but also nitrogen oxides, the latter statement began a long discussion that lasted until 1931, when D. Vorländer () proved the correctness of the observations of V. G. Khlopin.
  The circle of V. G. Khlopin's interests is not strictly confined to any one area. It is determined by the school, which he passed under the guidance of L. A. Chugaev and V. I. Vernadsky, respectively - in general chemistry and geochemistry, which, in turn, allowed V. G. Khlopin to develop his own scientific direction - to create the first domestic school of radiochemists.